Battery control systems
Various embodiments herein relate to the design of battery stacks, batteries and battery packs that are able to accommodate volumetric expansion in the battery materials. These designs may be especially useful in connection with batteries having negative electrodes made of lithium metal and/or positive electrodes made of an electrochemically active conversion material. These batteries may expand on the order of 10-40% during cycling. The battery designs disclosed herein include compressible regions that span a wide variety of different designs and implementations.
1. A battery comprising:
a boost pack and a primary energy pack;
(a) wherein the primary energy pack comprises a plurality of unit cells arranged as one or more rechargeable battery stacks, each unit cell comprising:
(i) a positive electrode layer;
(ii) a lithium metal negative electrode layer;
(iii) a solid-state electrolyte layer positioned between the positive electrode layer and the negative electrode layer;
(iv) a positive current collector layer in electrical contact with the positive electrode layer; and
(v) a negative current collector layer in electrical contact with the negative electrode layer;
wherein the boost pack has a capacity of about 1-20 kWh and wherein the primary energy pack has a capacity of about 50-150 kWh;
wherein the boost pack has a power capability of about 60-200 kW peak and about 30-80 kW continuous, and wherein the primary energy pack has a power capability of about 60-300 kW peak and about 30-100 kW continuous;
(b) one or more compressible structures configured to apply pressure to the battery stacks during expansion of the one or more battery stacks during charge; and
(c) a confinement structure about the one or more stacks and the one or more compressible structures.
2. The battery of claim 1 , wherein the one or more compressible structures, taken together, accommodate at least about 10% volumetric expansion in the one or more battery stacks during charge.
3. The battery of claim 1 , wherein the one or more compressible structures comprise a single compressible structure positioned proximate the one or more battery stacks, and wherein the confinement structure is a battery can.
4. The battery of claim 1 , wherein the one or more compressible structures are positioned between at least two of the battery stacks, and wherein the confinement structure is a battery can.
5. The battery of claim 1 , wherein the one or more compressible structures are positioned between adjacent unit cells of the stack.
6. The battery of claim 5 , wherein the one or more compressible structures are positioned between layers of positive current collectors and/or between layers of negative current collectors of adjacent unit cells of the stack.
7. The battery of claim 1 , wherein at least one of the positive or negative current collector layers is also one of the compressible structures.
8. The battery of claim 7 , wherein the compressible structure that is one of the positive or negative current collector layers is selected from the group consisting of a carbon nanofoam, an aerogel, and non-woven carbon fiber.
9. The battery of claim 1 , wherein the one or more rechargeable battery stacks and the one or more compressible structures have a compressible/cell ratio between about 0.001-2.
10. The battery of claim 1 , wherein the positive electrodes comprise FeF 3 .
11. The battery of claim 1 , wherein the one or more compressible structures comprise a compressible material having a low compression set, wherein the resilience properties of the compressible structures are stable at temperatures between about 60-100° C.
12. The battery of claim 1 , wherein at least one of the compressible structures is provided in the form of a block.
13. The battery of claim 1 , wherein at least one of the compressible structures comprises at least one plate and at least one compressible member.
14. The battery of claim 13 , wherein the plate is rigid.
15. The battery of claim 13 , wherein the plate is flexible.
16. The battery of claim 13 , wherein the plate includes a mechanism for maintaining the at least one compressible member in position.
17. A battery pack comprising:
a boost pack and a primary energy pack;
(a) wherein the primary energy pack comprises one or more battery stacks, each sealed in flexible pouches, wherein each of the one or more battery stacks comprise one or more unit cells, each comprising:
(i) a positive electrode layer,
(ii) a lithium metal negative electrode layer,
(iii) an electrolyte layer positioned between the positive electrode layer and the negative electrode layer,
(iv) a positive current collector layer in electrical contact with the positive electrode layer, and
(v) a negative current collector layer in electrical contact with the negative electrode layer;
wherein the boost pack has a capacity of about 1-20 kWh and wherein the primary energy pack has a capacity of about 50-150 kWh;
wherein the boost pack has a power capability of about 60-200 kW peak and about 30-80 kW continuous, and wherein the primary energy pack has a power capability of about 60-300 kW peak and about 30-100 kW continuous; and
(b) one or more compression structures positioned such that the one or more compression structures compress as the one or more battery stacks expand on charge, and such that the one or more compression structures expand as one or more battery stacks decrease in volume on discharge.
18. A process for detecting an idle state charge, the process comprising:
providing a vehicle having a battery with a boost pack and a primary energy pack, (a) wherein the primary energy pack comprises a plurality of unit cells arranged as one or more rechargeable battery stacks, each unit cell comprising:
(i) a positive electrode layer;
(ii) a lithium metal negative electrode layer;
(iii) a solid-state electrolyte layer positioned between the positive electrode layer and the negative electrode layer;
(iv) a positive current collector layer in electrical contact with the positive electrode layer; and
(v) a negative current collector layer in electrical contact with the negative electrode layer;
(b) one or more compressible structures configured to apply pressure to the battery stacks during expansion of the one or more battery stacks during charge; and
(c) a confinement structure about the one or more stacks and the one or more compressible structures,
wherein the boost pack has a capacity of about 1-20 kWh and wherein the primary energy pack has a capacity of about 50-150 kWh;
wherein the boost pack has a power capability of about 60-200 kW peak and about 30-80 kW continuous, and wherein the primary energy pack has a power capability of about 60-300 kW peak and about 30-100 kW continuous;
detecting if the vehicle is in an off state or an on state;
detecting if the boost pack is below a threshold value;
charging the boost pack if the boost pack is below a threshold value; and
charging the primary energy pack with either the boost pack or an external charger, if an external charger is present.
19. The process of claim 18 , further comprising heating the primary energy pack by discharging the boost pack.
20. The battery of claim 1 , wherein the boost pack comprises a plurality of second unit cells arranged as one or more second rechargeable battery stacks, each second unit cell comprising:
(i) a second positive electrode layer;
(ii) a second negative electrode layer;
(iii) a liquid electrolyte or a second solid-state electrolyte layer positioned between the positive electrode layer and the negative electrode layer;
(iv) a second positive current collector layer in electrical contact with the second positive electrode layer; and
(v) a second negative current collector layer in electrical contact with the second negative electrode layer.
21. The battery of claim 17 , wherein the boost pack comprises a plurality of second unit cells arranged as one or more second rechargeable battery stacks, each second unit cell comprising:
(i) a second positive electrode layer;
(ii) a second negative electrode layer;
(iii) a liquid electrolyte or a second solid-state electrolyte layer positioned between the positive electrode layer and the negative electrode layer;
(iv) a second positive current collector layer in electrical contact with the second positive electrode layer; and
(v) a second negative current collector layer in electrical contact with the second negative electrode layer.